In the art of conveyors made from the assembly of a large number of substantially identical modular belt links there are generally two types of conveyors, i.e. straight running and flexible conveyors. The present invention is particularly directed to the so-called flexible conveyors, i.e. conveyors which may be used in conveyor systems where turns or gradients are encountered, but may also be used for straight-running conveyors.
When a conveyor belt of the type mentioned above runs through a turn, be it a single turn in a conveyor path or in a spiral conveyor having a substantially constant turn, the outermost edge of the conveyor belt will have a tendency to lift itself up from the underlying carrying structure due to the tensions arising in the belt. In order to counter this it is quite widespread to provide means underneath the belt, typically by providing special edge modules which are provided with means for holding down the belt such that the belt will be in steady contact with the underlying structure at least when the belt would otherwise lift itself off the sub-structure. Thereby is created a smoother travel of the belt in relation to the substructure. One such means is a tab which projects downwards and outwards such that it may engage a special flange provided in the substructure whereby the modular conveyor belt in this manner is physically guided vertically by the substructure, but may naturally move completely free in the transport direction which normally is substantially horizontal. This solution normally requires that at least two types of belt modules are used, i.e. a standard belt module for the major part of the conveyors load carrying surface and a special edge module comprising such a downwardly projecting tab in each row.
Although this is a widespread solution it does have some drawbacks which the present invention addresses. Among these drawbacks is the fact that when constructing a modular conveyor belt of the type mentioned above two different types of modules must be used such that the robots or personnel assembling the modular belt must pay special attention to placing the special modules in the correct positions. This in turn requires at least two different sets of moulds for providing injection moulding equipment for manufacture of the modular belt links. A further disadvantage is the fact that depending on how many turns and how sharp these turns are the tab is exposed to excessive wear such that usually the tab will wear out much faster than the conveyor belt module as such, which in turn will require replacement at least of the edge modules a long time before they have expired their active service life, had they been regular modular belt links.